Plans and progress
- Useful links
Plans and progress
- Useful links
I recently received this message from a fellow MGF Turbo converter, I have anonymised it, copied here with my reply so everybody can see the correspondence as it is of general interest.
Thanks for your reply, it seems a few members in the MG community are now seeing the potential in a turbocharged MGF/TF, 200BHP and 270NM of torque seems to be rather appealing! Personally I can only see this as a good thing, if it takes off maybe we'll see more development in updated turbo internals and the prices of our little motors might even start to rise (Not that that’s why I’m looking to turbocharge!).
My overall goal is to turbo my F with as many factory components as possible for two reasons mainly.
Generally OEM components are made and tested to a far higher standard than aftermarket parts and often they can be picked up cheap if others are removing these parts to upgrade etc.
Which brings me on to the cooling front, I'm going to run a charge cooler from a Ford Focus RS Mk1 which seems a nice size (Roughly the same size as our air box) and should suit our application perfectly as the Focus puts out over 200BHP from factory, as bonus these come up for sales when the Focus guys chase 300BHP+ and they upgrade to front mount intercoolers.
For oil cooling I was planning on running an oil to water cooler, in addition to my twin cooling fans and PRT. If needed I might also increase the core size of the radiator and running the engine bay fan constantly but I'm hoping this won't be necessary.
When I say reasonable cost I'm talking less than £800 (I’ve already been quoted this much) because we really don't need a fancy equal length manifold. The standard 75/ZT log manifold can produce more power than the standard internals can handle and with the limited supply of forged turbo length con-rods and matching pistons the 200-205BHP limit seems a nice amount although 215BHP would be nicer though as it works out as 160Kw.
As for the rest of my exhaust system, I'm currently running a 200 cell Janspeed sports cat (Still passes MOT emissions test) and a Trevor Taylor MK7 straight through backbox, both of these items are 56mm bore so I can’t see there been too much pressure in my system either fingers crossed!
How are you planning to lay out your manifold (i.e. will the turbo sit in its normal orientation? With the air intake pointing forwards the passenger side duct) and will it be designed with the standard Garrett GT2052LS turbo in mind?
Thanks for your very interesting email. It seems that you and I are on pretty much the same track with our philosophies on how to turbocharge the MGF for road use.
I would have gone the same way as you with the Ford charge cooler system if I had been able to find one, all I found was a header tank so I snapped that up.
I believe the standard engine internals are probably ok for road use, the only difference to the n/a engines is the 2mm shorter con-rods and I think the turbo has different rings on the same pistons as the 160 n/a engines. You are right, so far as I know 2mm shorter forged steel con-rods do not exist.
Am guessing the shorter con-rod was MG Rovers cheap way of reducing static compression ratio for the turbo engine, but that reduces the "squish" effect generating useful turbulence in combustion chamber as pistons reach TDC. This is a compromise for road use but a better and I guess more expensive way would have been bowled pistons or higher volume combustion chamber.
Another compromise the shorter con-rods require is the acceptance of greater con-rod angles which push the piston harder against the bore as it rises and falls = possible increased friction and wear. Maybe this is why the turbo has different piston rings?
I do not know if it is possible to enlarge the combustion chamber at all or sufficiently to allow use of steel standard length con-rods and proper competition forged pistons a la n/a race engines to retain the "squish". Would have to ask a K series head modding expert if it could be done but I have my doubts.
But while heat and compression stresses in the turbo engine are higher, inertia stress is much reduced as turbo engines produce their best goods about 2000rpm lower than n/a engines. This is one reason why I want to go turbo with my cars - I am changing the gearing for longer legs but will write more about that later.
We differ on oil cooling. I see that you intend to use the later standard laminova (I think it is called that) oil-water heat exchanger to cool the oil. This is great for warming the oil up faster from cold starts as water heats up much faster and will transfer heat to the oil. But when engine is thoroughly warmed up/hot the oil is at higher temperature than the water, particularly with turbo engines, so will transfer extra heat into the engine water cooling system to be dissipated by the water radiator. This is further loading the water cooling system, making it work harder than it needs to do.
I am going the way of a conventional front mounted 13 row oil cooler with a thermostatic sandwich plate. This will positively assist the water cooling system as it will be an additional route for heat to leave the engine and dissipating it entirely additionally to the water cooling system. It will also considerably increase the total oil capacity - no bad thing. As the sandwich plate will move the oil filter towards the exhaust downpipe and as the downpipe will itself be moving towards the oil filter due to turbo relocation there may well be a (hot) location conflict. I plan to get around this by using a remote filter kit and relocate the oil filter to the front compartment near to the oil cooler. Even if it doesn't need to be done from the packaging viewpoint it will be beneficial in moving the oil filter from a hot environment to a cold one!
Talking about exhaust manifolds. I was originally planning a log style manifold but my researches led me to believe this was a bad idea when an equal length manifold solution offered itself for much the same money and effort and would give greater efficiency and flexibility.
By flexibility I mean that I am designing the manifold so there can be two versions - short runner for fast spool up/minimum lag and tending towards torque rather than bhp for road cars and a long runner version for those chasing bhp at the expense of torque and lag for their land speed record or drag race cars ;-). It is impossible to explain here in words how I'm doing it but the geometry will be clear in the build photos when we make the runners. Basically, the geometry which will make equal length runners easy to achieve will also make adjustable length runners just as easy! My runners will also have identical degrees of bends and identical length of straight pipe so will be balanced in every possible way. The ZandF Tuning remap of an otherwise completely standard MGZT-T is claimed to give 204bhp, with my better manifold and downpipe I'm hoping that figure may rise to the 215 you are craving ;-)
Talk of log manifolds is making me want to also make up a log version from the mild steel parts I have gathered together which would otherwise not now be used. I may well do that when the conversion is completed and fit it temporarily so that we can do a rolling road comparison with nothing else changing.
Your exhaust system sounds super, the Janspeed sport cat and Trevor Taylor system are beautiful things, I looked at pictures just now. My 61mm bore downpipe will be designed to connect to standard cat so that all options of exhaust system remain open though I plan to make a 200 cell 61mm bore fully stainless sport cat which will be a direct replacement of standard.
When I briefly had a T16 engined BRM it came without a cat so I bought a Motobuild 200 cell sport cat for it. I quickly p/x'ed that horrible car for the Trophy 160 before fitting the cat so it was spare on the garage shelf. We chopped the small T series pipes and flanges from it and welded on 61mm bore tubes and flanges to make a "home brewed" sport cat to use with the Janspeed EM997 manifold on my K series BRM. It has been there for quite a while now in daily use and has passed two MOT emissions tests easily with a Piper 270 on the exhaust side. The local MOT garage proprietor knows me, Alex my mobile mechanic who did his apprenticeship there, and my also boss well and told me that so long as the car has a cat, it is in the original position and passes emissions tests he doesn't care how it was made...
Yes the turbo will be oriented as standard and use the standard Garrett GT2052LS as this is what the off-the-shelf ZandF Tuning map was developed for. I was tempted to try turning turbo through 180 degrees to move the it away from bulkhead and towards the engine block but that would have led the downpipe to point towards the passenger side of car, ie as Alex pointed out, close to rubber cooling pipes and plastic petrol tank so we stepped away from that thought. And if it is left in standard orientation the turbo cold air intake will remain pointing towards the passenger side air intake - useful.
I too have a PRT setup waiting on the shelf but don't know yet whether I shall fit it. Mainly because I have no idea how it is plumbed in but also because its' position will be in an already crowded location, especially when turbo and its' associated plumbing are fitted. Shall look at that option when turbo etc are in position and decide then.
We're off to an MG Car Club race meeting at Brands tomorrow - shall be putting some biz cards under windscreen wipers in car park to generate some more interest.